"And she looks fun. And I'm sure she is a good influence on her husband. And I'm glad she was there for him during 9/11."

The 72-year-old Walters points out that at 65, Heinz Kerry  if Massachusetts Sen. John Kerry wins the White House  would be the oldest first lady ever to take office.

"Well, it's nice to be first," replies Heinz Kerry, who is also the first political spouse to sing the praises of Botox.

Her first husband, Republican Sen. John Heinz of Pennsylvania, was killed in a plane crash 13 years ago. So how's her nine-year marriage to Kerry going?

"It's a grown-up marriage," she tells Walters. "Your first marriage is your first marriage, you know . . . somebody for 30 years that I knew. My second marriage is a marriage that in some ways is easier, because you have a lot more maturation under your belt and so you don't kind of waste time with extraneous things  you don't hope for things that are not possible  you may be more generous and forgiving  but you're also more demanding in what's really important."

She also defends her husband, a decorated veteran of the Vietnam War, against Bush campaign critics such as Vice President Cheney, who avoided the draft during Vietnam.

"I tell you, if someone went to war and came back and didn't throw their medals in and criticized my husband, I'd say you have a right," she says. "But to be criticized by people who evaded going to war, I don't think is fair game."

JOAN RIVERS: "C-CLASS" AT BEST

It's sure not your father's Mercedes-Benz.

At Tuesday night's celebration of the newly redesigned 2005 C-Class cars, paid shill Joan Rivers gave the prestigious German automaker a wild ride in corporate rebranding.

During her "C-Class Facelift Comedy Night" at Time Cafe & Fez Theater, the wicked-tongued comedian's regular East Village venue, the 70-year-old Rivers repeatedly sang the praises of the C-Class  but steered her shtick through hairpin turns of vitriol, racial jokes, gross profanity and plain bad taste.

Among her targets were everyone from the Olsen twins to the late Jacqueline Onassis.

Most of the "jokes" were so nasty and vicious that we wouldn't stoop to try to repeat them here in a family newspaper.

Instead, we'll just give you these few samples of the least offensive:

On PETA people: "So (bleeping) ugly. I hate ugly people."

On dealing with her mother's ashes: "The Atlantic? Like I have time. I flushed them down the toilet. I'm convinced they're going to lose my ashes  Whitney Houston is going to snort them. Melissa (Rivers' daughter) is going to have to hang wreathes on Bobby Brown's (rear end) every year."

Believe us, the ones we left out were a lot worse.

On Wednesday, Mercedes-Benz spokesman Joe Richardson explained: "It was just a fun tie-in with the redesign of a car. Not everybody will think a joke is funny. As soon as you try to please all the people all the time, that's not being a leader. By always going with what's safe, you're never going to break new ground."

THE BRIEFING

RED-FACED APOLOGY: Former Cosmopolitan magazine editor Helen Gurley Brown got herself into trouble at Thursday's Women Who Care lunch, sponsored by United Cerebral Palsy of New York City, when she introduced honoree Susan Kaskel. Addressing a crowd that included some severely disabled people at Tavern on the Green, Brown became highly annoyed at sound of keening moans. "Who is making that noise?" Brown interrupted her remarks to demand. "Can someone please make that child be quiet?" It was too late by the time a mortified Brown learned it was a middle-aged cerebral palsy victim. "What can I say? I thought it was a child cutting up," Brown told me. "I now realize how wrong I was, and I want everybody to know how profoundly sorry I am."

NOT THAT THERE'S ANYTHING WRONG WITH THAT: Speaking to People magazine's sales and marketing staff Thursday, Donald Trump admitted to being attracted to Rob Lowe. "You know I love beautiful women," the reality television star confided. "This is the most beautiful guy I've ever seen."